For information concerning the overall classification of Solanaceae and the relationships of the genera, the references below may be useful as a starting point. The family continues to be under scrutiny and there are likely to be some further changes, particularly within the alignment of the genera. For instance as a result of molecular studies Cyphomandra and Lycopersicon are now considered to be part of Solanum and Lycianthes is treated as separate from Solanum, while the relationships of Symonanthus, Nicotiana and the Anthocercideae are under review and membership of the Cyphanthera needs to be revisited.

The classification used for the Australian genera in this key is now somewhat out of date but useful as a framework - see Tribal placement of genera. For more up to date accounts and summaries of ongoing work in the family see Solanaceae Source, a growing resource on the systematics and phylogeny of Solanaceae, particularly Solanum, and the Angiosperm Phylogeny Website with consideration of all of the latest work on the classification of Solanales and Solanaceae. Further works which involve the consideration of Australian taxa can be found under References.

Classification at the species level will also continue to change as we learn more about the Australian species.

There are likely to be considerable changes within the classification of the native species of Solanum in Australia. David Symons foundation work to put the whole of Solanum for Australia on a sound basis (Symon 1981) suffered as many of such works do, from inadequate collections and field work, despite David growing many of the species from seed. However the framework he supplied has allowed Tony Bean in Queensland to concentrate field work in that state (an area which David did not visit), and this has revealed considerably more species than was originally suspected. Tony too was able to look in more detail at complexes and characters, such as hair type, which David was not able to do. As a result of these studies Tony has published considerably more detailed species descriptions and there is a need for comparative descriptions of all of the Australian species. This may also help in the achievement of a better defined species concept for the group since those recognised in the later works appear to be more narrowly defined than in the earlier works.

Likewise the molecular studies of Chris Martine have exposed some problems with the taxonomy and relationships of the difficult dioecious species of Solanum of northern Australia. These dioecious species are not only more difficult to access but also require field observations to work out their biology and thus understand their taxonomy, and there will undoubtedly be some changes in the future.

At the moment the well-known difficulties of Nicotiana species discrimination have not been resolved and it is expected that users will still struggle with the key provided. Future molecular work on the genus may provide some answers here.